Gas continuous analysis system, and gas continuous analysis method

Abstract

The present invention reduces time for calibration or validation of an analyzer for analyzing a sample gas containing an adsorbable component, and comprises a main flow passage through which the sample gas containing the adsorbable component flows, an analyzer for analyzing the adsorbable component in the sample gas flowing through the main flow passage, a reference gas flow passage for supplying a reference gas for performing calibration or validation of the analyzer, and a purge gas flow passage for supplying a purge gas containing moisture to the analyzer, wherein: the sample gas is introduced into the main flow path, and the sample gas is continuously analyzed by the analyzer; midway through the continuous analysis the purge gas is supplied to the analyzer from the purge gas flow passage to purge the analyzer; and then the reference gas is supplied to the analyzer from the reference gas flow passage and the analyzer is calibrated or validated.

Description

Continuous gas analysis system and continuous gas analysis method

[0001] The present invention relates to a continuous gas analysis system and a continuous gas analysis method.

[0002] Conventionally, in a method for continuously analyzing gases (e.g., flue gases, process gases, etc.) emitted from industrial facilities such as industrial waste disposal sites and chemical plants, the gases are sampled and introduced into an analyzer. Then, during this continuous analysis, the analyzer is calibrated (zero calibration, span calibration). Zero calibration is performed for example on nitrogen (N ２ ) gas, and span calibration is performed using a span gas containing a measured component of known concentration.

[0003] However, when analyzing adsorbent components contained in gas, such as hydrogen fluoride (HF) and hydrogen chloride (HCl), the adsorbent components are adsorbed to the inner surfaces of the piping and the analyzer's measurement cell. When zero gas is flowed during calibration, the adsorbent components adsorbed in the cell are desorbed from the measurement cell. This causes a long time for the analyzer's readings to stabilize during calibration. As a result, the calibration time between consecutive analyses becomes longer, resulting in longer interruptions to the continuous gas analysis.

[0004] JP 2013-96889 A

[0005] Therefore, the present invention has been made to solve the above-mentioned problems, and its main object is to shorten the time required for calibration or validation of an analyzer that analyzes sample gas containing adsorbent components.

[0006] That is, the continuous gas analysis system according to the present invention comprises a main flow path through which a sample gas containing an adsorbent component flows, an analyzer that analyzes the adsorbent component in the sample gas flowing through the main flow path, a standard gas flow path that supplies a standard gas for calibration or validation to the analyzer, and a purge gas flow path that supplies a purge gas containing moisture to a flow path of the analyzer through which the sample gas passes, and is characterized in that the sample gas is introduced into the main flow path and continuously analyzed by the analyzer, the purge gas is supplied from the purge gas flow path to the analyzer during the continuous analysis to purge the flow path of the analyzer through which the sample gas passes, and subsequently the standard gas is supplied from the standard gas flow path to the analyzer to calibrate or validate the analyzer.

[0007] In this continuous gas analysis system, the flow path through which the sample gas of the analyzer passes is purged using a purge gas containing moisture before the analyzer is calibrated or validated, thereby shortening the time until the analyzer reading stabilizes during calibration or validation. Here, because a purge gas containing moisture is used, adsorbent components adsorbed to the inner surface of the flow path through which the sample gas passes, such as the measurement cell of the analyzer, are more likely to be desorbed by water molecules. As a result, the time required for calibration or validation performed between continuous analyses can be shortened, thereby shortening the interruption time of continuous sample gas analysis.

[0008] A specific embodiment of the purge gas flow path may be one that supplies atmospheric air to the flow path through which the sample gas of the analyzer passes, thereby reducing the cost of purge gas.

[0009] As a specific embodiment of the analyzer, the adsorbable components HF, HCl or NH ３ Here, the dipole moment, which is an index of the ease of adsorption, is calculated by H ２ O>HF>NH ３ >HCl, and the adsorbable component is HF, HCl or NH ３In a system for analyzing the above, the effect of using a purge gas containing moisture can be significantly enhanced.

[0010] The standard gas flow path may include a zero calibration gas flow path for supplying a zero calibration gas to the analyzer, and a span calibration gas flow path for supplying a span calibration gas to the analyzer. In this configuration, in order to shorten the calibration time for zero calibration and the calibration time for span calibration, it is desirable that the continuous gas analysis system supplies the purge gas from the purge gas flow path to the analyzer during the continuous analysis to purge a flow path through which the sample gas of the analyzer passes, then supplies the zero calibration gas from the zero calibration gas flow path to the analyzer to zero calibrate the analyzer, and supplies the span calibration gas from the span calibration gas flow path to the analyzer to span calibrate the analyzer.

[0011] The standard gas flow path may not have a zero calibration gas flow path for supplying a zero calibration gas to the analyzer. In this case, the standard gas flow path supplies a span calibration gas to the analyzer, and the continuous gas analysis system preferably supplies the purge gas from the purge gas flow path to the analyzer during the continuous analysis to purge the flow path through which the sample gas of the analyzer passes and zero-calibrate the analyzer, and then supplies the span calibration gas from the standard gas flow path to the analyzer to span-calibrate the analyzer. With this configuration, zero-calibration can be performed by supplying a purge gas from the purge gas flow path without using a zero calibration gas flow path.

[0012] The main flow path can be purged downstream of the connection point of the purge gas flow path. However, the main flow path cannot be purged upstream of the connection point of the purge gas flow path. As a result, exhaust gas remains after the continuous analysis is completed, causing moisture in the exhaust gas to condense. This can cause measurement errors in subsequent continuous analysis. To suitably solve this problem, the continuous gas analysis system according to the present invention preferably further includes a second purge flow path connected to the upstream side of the analyzer in the main flow path and supplying a second purge gas from the connection point toward the upstream side of the main flow path, and the continuous exhaust gas analysis system preferably supplies the second purge gas from the second purge flow path after the continuous analysis is completed to purge the upstream side of the connection point of the second purge flow path.

[0013] HF, HCl or NH ３ When analyzing adsorbent components such as those described above, the adsorbent components may be adsorbed to the inner surface of the piping that constitutes the main flow path, slowing the response time of the analyzer. To effectively solve this problem, it is desirable to further provide an overflow flow path that discharges a portion of the sample gas flowing through the main flow path upstream of the analyzer. With this configuration, the overflow flow path can increase the flow rate of the sample gas introduced into the main flow path. As a result, it is possible to make it difficult for adsorbent components to be adsorbed to the inner surface of the piping that constitutes the main flow path.

[0014] As a configuration for shortening the distance from the overflow flow path to the analyzer, it is desirable that a throttle section be provided in the main flow path between the connection point of the overflow flow path and the analyzer, that a main suction pump be provided in the main flow path downstream of the analyzer, and that a sub-suction pump be provided in the overflow flow path.

[0015] The continuous gas analysis system according to the present invention is characterized by comprising a sampling unit that samples gas containing adsorbent components flowing through a duct; a main flow path through which the sample gas sampled by the sampling unit flows; a chromatograph or mass spectrometer that analyzes the adsorbent components in the sample gas flowing through the main flow path; and an overflow flow path that discharges a portion of the sample gas flowing through the main flow path upstream of the analyzer. With this configuration, the overflow flow path allows the sample gas introduced into the main flow path to have a high flow rate. As a result, it is possible to make it difficult for adsorbent components to be adsorbed on the inner surface of the piping that constitutes the main flow path, thereby improving the analytical accuracy of the chromatograph or mass spectrometer. This also leads to an improvement in the response time of the chromatograph or mass spectrometer.

[0016] Furthermore, a continuous gas analysis method according to the present invention is a method using a measurement system including a main flow path through which a sample gas containing an adsorbent flows, an analyzer that analyzes the adsorbent components in the sample gas flowing through the main flow path, a standard gas flow path that supplies a standard gas for calibration or validation to the analyzer, and a purge gas flow path that supplies a purge gas containing moisture to a flow path of the analyzer through which the sample gas passes, characterized in that the sample gas is introduced into the main flow path and continuously analyzed by the analyzer, the purge gas is supplied from the purge gas flow path to the analyzer during the continuous analysis to purge the flow path of the analyzer through which the sample gas passes, and subsequently the standard gas is supplied from the standard gas flow path to the analyzer to calibrate or validate the analyzer.

[0017] According to the present invention configured as described above, it is possible to reduce the time required for calibration or validation of an analyzer that analyzes a sample gas containing an adsorbent component.

[0018] FIG. 1 is a schematic diagram showing a continuous gas analysis system according to one embodiment of the present invention. FIG. 1 is a schematic diagram showing the internal configuration of a housing that houses an analyzer of the same embodiment. FIG. 2 is a schematic diagram showing the flow of sample gas during continuous analysis of the same embodiment. FIG. 3 is a schematic diagram showing the flow of purge gas (atmosphere) during purge processing of the same embodiment. FIG. 4 is a schematic diagram showing the flow of zero gas during zero calibration of the same embodiment. FIG. 5 is a schematic diagram showing the flow of span gas during span calibration of the same embodiment. FIG. 6 is a schematic diagram showing the flow of second purge gas after completion of continuous analysis of the same embodiment (before or when the system is stopped). FIG. 7 is a schematic diagram showing a continuous gas analysis system according to a modified embodiment. FIG. 8 is a schematic diagram showing a continuous gas analysis system according to a modified embodiment.

[0019] An embodiment of a continuous gas analysis system according to the present invention will be described below with reference to the drawings. Note that, for ease of understanding, all of the drawings shown below are drawn in a schematic manner, with appropriate omissions or exaggerations. Identical components are designated by the same reference numerals, and their description will be omitted where appropriate.

[0020] The continuous gas analysis system 100 according to this embodiment detects hydrogen fluoride (HF), hydrogen chloride (HCl), or ammonia (NH ３ The concentration of adsorbent components such as urea, urea, and urea is continuously analyzed.

[0021] Here, the sample gas refers to combustion gas or process gas, such as combustion gas or combustion exhaust gas (flue gas). Combustion gas refers to gas being burned in an external combustion engine, industrial furnace, incinerator, turbine, or power plant, while combustion exhaust gas refers to post-combustion gas discharged from an external combustion engine, industrial furnace, incinerator, turbine, or power plant. Process gas refers to gas in chemical plants, such as petrochemical, coal chemical, natural gas chemical, oil refinery, methanation, and gasification plants, and includes raw material gases such as natural gas, as well as gases separated or generated in chemical plants. Furthermore, process gas includes gas that has passed through a scrubber, which is an exhaust gas treatment facility in a semiconductor manufacturing plant (semiconductor manufacturing equipment), such as exhaust gas from an etching device, which is passed through a scrubber to remove HF and other compounds produced by decomposition reactions from the exhaust gas. Alternatively, the sample gas may be any of the above gases after being detoxified.

[0022] Specifically, as shown in FIG. 1 , the continuous gas analysis system 100 includes a main flow path 2 through which a sample gas containing an adsorbent component flows, an analyzer 3 that analyzes the adsorbent component in the sample gas flowing through the main flow path 2, a calibration gas flow path 4 that is a standard gas flow path that supplies a calibration gas that is a standard gas to the analyzer 3, a purge gas flow path (first purge gas flow path) 5A that supplies a purge gas (first purge gas) containing moisture to the flow path through which the sample gas of the analyzer 3 flows, a second purge flow path 5B that is connected to the main flow path 2 on the upstream side of the analyzer 3 and supplies a second purge gas from the connection point toward the upstream side of the main flow path 2, and an overflow flow path 6 that discharges a portion of the sample gas flowing through the main flow path 2 on the upstream side of the analyzer 3.

[0023] A sampling unit 7 is provided at one end of the main flow path 2 for sampling gas flowing through, for example, the flue. This sampling unit 7 has a sampling probe 7P that is inserted into the flue formed by the duct D, and gas is sampled from this sampling probe 7P. The sampling unit 7 is provided with a dust collection filter 71. The main flow path 2 is configured with hot hoses 21 from the sampling unit 7 to the housing 8 that houses the analyzer 3. The hot hoses 21 can be made of Teflon to prevent adsorption of adsorbent components. In FIG. 2, reference numeral 8F denotes a ventilation unit such as a fan provided on the wall of the housing 8.

[0024] Specifically, the main flow path 2 is provided downstream of the hot hose 21 with a dust collection filter 2a, a throttle 2b such as an orifice, an analyzer 3, and a main suction pump 2c, in this order from upstream to downstream. Additionally, the main flow path 2 is provided with an electromagnetic on-off valve 2d upstream of the dust collection filter 2a. A pressure sensor 2e, a flow rate sensor 2f, a check valve 2g, or a pressure regulating valve 2h may be provided in the main flow path 2 between the analyzer 3 and the main suction pump 2c. In this embodiment, the pressure regulating valve 2h and the main suction pump 2c are provided outside the housing 8. Furthermore, the piping downstream of the main suction pump 2c in the main flow path 2 may be heated to prevent moisture condensation. The heating temperature can be set according to the moisture concentration in the sample gas. For example, if the moisture concentration in the sample gas is 6 vol%, the heating temperature may be set to 40°C. A dehumidifier or buffer tank may be provided downstream of the main suction pump 2c to remove moisture from the sample gas. The upstream side of the main suction pump 2c is decompressed and does not need to be heated, but it may be heated or a dehumidifier or a buffer tank may be provided.

[0025] The analyzer 3 detects HF, HCl, or NH ３ The concentration of is continuously analyzed, and for example, an IRLAM detector using the infrared laser absorption modulation method (see Japanese Patent No. 6886507) is used.

[0026] Specifically, as shown in Figures 1 and 2, the analyzer 3 includes a measurement cell 31 into which a sample gas is introduced, a semiconductor laser 32 that irradiates the measurement cell 31 with laser light, a photodetector 33 that receives the laser light that has passed through the measurement cell 31, and a signal processing unit 34 that receives an output signal from the photodetector 33 and calculates the concentration of the measurement component based on the output signal. The measurement cell 31 has an inlet port P1 for introducing the sample gas and an outlet port P2 for discharging the sample gas, and is internally provided with a pair of reflecting mirrors M1 and M2, making it a so-called Herriott cell that multiple-reflects the laser light. The temperature of the measurement cell 31 is controlled to a predetermined temperature based on the temperature detected by a temperature sensor 35. The concentration of the measurement component obtained by the signal processing unit 34 is displayed on a display unit 10, such as a display.

[0027] Here, the semiconductor laser 32 may be a quantum cascade laser, an interband cascade laser, or any other semiconductor laser.

[0028] A quantum cascade laser is a semiconductor laser that uses intersubband transitions in a multistage quantum well structure and oscillates laser light of a specific wavelength in the wavelength range of about 4 μm to about 20 μm. An interband cascade laser is a semiconductor laser that uses interband transitions in a multistage PN junction in a quantum well structure and oscillates laser light of a specific wavelength in the wavelength range of about 3 μm to about 5 μm. Other semiconductor lasers are semiconductor lasers that use interband transitions in a single PN junction in a quantum well structure and are semiconductor lasers that can oscillate ultraviolet light, visible light, and near-infrared light mainly in the wavelength range of 0.3 μm to 3 μm.

[0029] Furthermore, as shown in FIG. 2, the semiconductor laser 32 may be configured to include multiple semiconductor lasers 32. In this case, the multiple semiconductor lasers 32 may be configured to emit laser beams of different wavelengths according to the components to be measured. Here, the multiple semiconductor lasers 32 may be configured to emit laser beams at different timings, or at least two or more may be configured to emit laser beams simultaneously. Furthermore, multiple reflecting mirrors 36a to 36h may be provided to guide the laser beams emitted from the multiple semiconductor lasers 32 into the measurement cell 31. The laser beams that pass through the measurement cell 31 are reflected by a reflecting mirror 36i and detected by a photodetector 33. In FIG. 2, the reference numeral 8X denotes a piping system (such as the main flow path 2, the calibration gas flow path 4, the first purge gas flow path 5A, the second purge flow path 5B, or the overflow flow path 6) provided within the housing 8 for introducing a sample gas, a purge gas, or a calibration gas into the measurement cell 31, with the piping system omitted.

[0030] The calibration gas flow path 4 is connected to the main flow path 2 on the upstream side of the analyzer 3, and supplies calibration gas to the main flow path 2. In this embodiment, the calibration gas flow path 4 is connected to the main flow path 2 on the upstream side of the dust collecting filter 2a, specifically, between the electromagnetic on-off valve 2d and the dust collecting filter 2a.

[0031] Specifically, the calibration gas flow path 4 is, for example, N ２ The analyzer 3 includes a zero gas flow path 41 that supplies zero gas, such as a gas, to the analyzer 3, and a span gas flow path 42 that supplies span gas of known concentration to the analyzer 3. In this embodiment, the zero gas flow path 41 and the span gas flow path 42 merge and are connected to the main flow path 2. A plurality of span gas flow paths 42 may be provided to supply various types of span gas (represented by "SPAN1 to SPAN4" in FIG. 1). Each calibration gas flow path 41, 42 is provided with an electromagnetic on-off valve 41a, 42a, allowing switching between the supply of each calibration gas. Additionally, each calibration gas flow path 41, 42 may be provided with a pressure adjustment valve 41b, 42b and a flow rate adjustment needle valve 41c, 42c.

[0032] The first purge gas flow path 5A is connected to the main flow path 2 upstream of the analyzer 3 and supplies a first purge gas containing moisture to the main flow path 2, thereby supplying the first purge gas containing moisture to the flow path through which the sample gas of the analyzer 3 flows. In this embodiment, the first purge gas flow path 5A supplies atmospheric air as the first purge gas containing moisture to the flow path through which the sample gas of the analyzer 3 flows. For this purpose, a dust collection filter 51 is provided in the air inlet 50 of the first purge gas flow path 5A. The first purge gas flow path 5A is connected to the main flow path 2 upstream of the dust collection filter 2a, specifically, between the electromagnetic on-off valve 2d and the dust collection filter 2a. The first purge gas flow path 5A also merges with the calibration gas flow path 4 and is connected to the main flow path 2. This allows the first purge gas flow path 5A to supply atmospheric air as the first purge gas to the calibration gas flow path 4. The first purge gas flow path 5A is provided with an electromagnetic on-off valve 5a, which is configured to switch the supply of the first purge gas.

[0033] The second purge gas flow path 5B is connected to the main flow path 2 upstream of the analyzer 3. The second purge gas is supplied to the main flow path 2 and upstream of the connection point of the second purge gas flow path 5B. In this embodiment, the second purge gas is reversed into the main flow path 2 to purge the exhaust gas remaining in the main flow path 2 and then discharged to the outside through the sampling unit 7. Although not shown, a second purge gas source (not shown) that pressurizes the second purge gas is connected to the upstream side of the second purge gas flow path 5B. Here, dry air, nitrogen gas, or the like can be used as the second purge air. Specifically, the second purge air flow path 5B is connected to the main flow path 2 upstream of the electromagnetic on-off valve 2d. A three-way valve 2i is provided at the connection point of the main flow path 2 with the second purge gas flow path 5B. The three-way valve 2i may be a manual selector valve or an electromagnetic selector valve. The electromagnetic on-off valve 2d of the main flow path 2 may be a three-way valve, and the second purge gas flow path 5B may be connected to this electromagnetic on-off valve 2d.

[0034] The overflow flow path 6 is connected to the main flow path 2 upstream of the analyzer 3 and discharges a portion of the sample gas flowing through the main flow path 2. In this embodiment, the overflow flow path 6 is connected upstream of the dust collection filter 2a in the main flow path 2, specifically, between the electromagnetic on-off valve 2d and the dust collection filter 2a. In other words, only the dust collection filter 2a and the throttle section 2b are provided between the connection point 6x of the overflow flow path 6 and the analyzer 3, minimizing the distance from the connection point 6x of the overflow flow path 6 to the analyzer 3. The overflow flow path 6 is also provided with a sub-suction pump 6a. A needle valve 6b for adjusting the flow rate may be provided upstream of the sub-suction pump 6a, and a flow sensor 6c may be provided downstream of the sub-suction pump 6a. In this embodiment, the sub-suction pump 6a, the needle valve 6b, and the flow sensor 6c are provided outside the housing 8. In this embodiment, the piping outside the housing 8 in the overflow flow path 6 may be heated to prevent condensation. Here, the heating temperature can be set according to the moisture concentration in the sample gas, and when the moisture concentration in the sample gas is, for example, 6 vol %, the heating temperature can be set to, for example, 40° C. Furthermore, a dehumidifier or buffer tank or the like may be provided in the piping outside the housing 8 in the overflow flow path 6 to remove moisture from the sample gas.

[0035] Furthermore, a bypass path 9 that bypasses the sub-suction pump 6a is connected to the overflow path 6. A three-way solenoid valve 6d is provided at the upstream connection point between the overflow path 6 and the bypass path 9, allowing for switching between these paths. A check valve 6e may also be provided upstream of the three-way solenoid valve 6d in the overflow path 6. In this embodiment, the piping outside the housing 8 in the bypass path 9 may be heated to prevent moisture from condensing. The heating temperature can be set according to the moisture concentration in the sample gas. For example, if the moisture concentration in the sample gas is 6 vol%, the heating temperature may be set to 40°C. A dehumidifier or buffer tank may also be provided in the piping outside the housing 8 in the bypass path 9 to remove moisture from the sample gas.

[0036] The piping inside the housing 8 in the main flow path 2, the overflow flow path 6, or the bypass flow path 9 may be heated to prevent condensation of moisture. Specifically, in the main flow path 2, the piping connected to the hot hose 21 may be heated up to the orifice 2b. Here, the downstream side of the orifice 2b is decompressed by the main suction pump 2c, and does not necessarily need to be heated. Alternatively, a configuration may be adopted in which a portion that is prone to condensation depending on measurement conditions, usage conditions, etc. is heated partially.

[0037] Additionally, since the continuous gas analysis system 100 of this embodiment continuously analyzes corrosive gases such as hydrogen fluoride (HF) or hydrogen chloride (HCl) in a sample gas, the flow path through which the sample gas flows may be constructed of a material resistant to the corrosive gas. For example, the piping constituting the main flow path 2, the piping constituting the overflow flow path 6, and / or the piping constituting the bypass flow path 9 may be constructed of Teflon or stainless steel (e.g., SUS316L) pipes. When using stainless steel pipes, it is possible to use pipes with polished inner surfaces. Note that Teflon pipes are preferable for easy piping management. Furthermore, the measurement cell 31 may be constructed of a material resistant to the corrosive gas. For example, the measurement cell 31 may be made of stainless steel (e.g., SUS316L), and the reflecting mirrors M1 and M2 disposed inside the measurement cell 31 may be made of stainless steel (e.g., SUS316L) with gold-plated reflective surfaces. In addition to stainless steel, Hastelloy, Inconel, etc. may also be used.

[0038] <Operation of the Continuous Gas Analysis System 100> The operation of the continuous gas analysis system 100 of this embodiment will be described below with reference to Figures 3 to 7. The continuous gas analysis method is carried out by the operation of this continuous gas analysis system 100.

[0039] <Normal Analysis> During normal continuous analysis, as shown in Figure 3, sample gas is sampled from the sampling unit 7 at a flow rate equal to the sum of the suction flow rate of the main suction pump 2c provided in the main flow path 2 and the suction flow rate of the sub-suction pump 6a provided in the overflow flow path 6. A portion of the sample gas flowing through the main flow path 2 is introduced into the analyzer 3 through the dust collection filter 2a and the throttle unit 2b. The remaining sample gas is exhausted through the overflow flow path 6. The sample gas sucked by the main suction pump 2c and introduced into the analyzer 3 through the throttle unit 2b is at a constant flow rate, and the inside of the measurement cell 31 is in a reduced pressure state. In this state, the analyzer 3 continuously analyzes the concentration of the adsorbable component, HF or HCl.

[0040] <Calibration (including purging)> During the continuous analysis, a calibration process is periodically performed based on a predetermined schedule, for example. Prior to this calibration process, a first purging process is performed.

[0041] Specifically, as shown in FIG. 4 , a first purge gas is supplied from the first purge gas flow path 5A to the analyzer 3 to purge the flow path through which the sample gas of the analyzer 3 flows and a portion of the calibration gas flow path 4. Here, the flow path through which the sample gas flows is the flow path from the sample gas inlet port (not shown) of the analyzer 3 to the measurement cell 31. The portion of the calibration gas flow path 4 is the downstream portion of the junction where the first purge gas flow path 5A joins the calibration gas flow path 4. At this time, the electromagnetic on-off valve 2d of the main flow path 2 is closed, and the electromagnetic on-off valve 5a of the first purge gas flow path 5A is opened. In this state, the main suction pump 2c introduces moisture-containing air from the air inlet port 50 of the first purge gas flow path 5A into the measurement cell 31 of the analyzer 3. As a result, the adsorbent components adsorbed to the inner surface of the piping from the connection point of the first purge gas flow path 5A in the main flow path 2 to the measurement cell 31, the inner surface of the measurement cell 31, and the reflecting mirrors M1 and M2 are released and removed by water molecules.

[0042] Following the first purge process, the analyzer 3 is calibrated by supplying calibration gas from the calibration gas flow path 4 to the analyzer 3. In other words, the analyzer 3 is calibrated in a purged state.

[0043] First, as shown in Fig. 5, zero gas is supplied to the analyzer 3 from the zero gas flow path 41 to perform zero calibration. Here, the electromagnetic on-off valve 2d of the main flow path 2 is closed, and the electromagnetic on-off valve 41a of the zero gas flow path 41 is opened. In this state, the main suction pump 2c introduces zero gas from the zero gas flow path 41 into the measurement cell 31 of the analyzer 3. This performs zero calibration of the analyzer 3. Even if the calibration gas is supplied under pressure from a cylinder, the pressure difference at the connection point 6x when the sample gas (Fig. 3) or the first purge gas (Fig. 4) is flowed through the main flow path 2 can be minimized by opening the pressure gas to the atmosphere using the three-way electromagnetic valve 6d of the overflow flow path 6.

[0044] Next, as shown in FIG. 6 , span calibration is performed by supplying span gas to the analyzer 3 from the span gas flow path 42. Here, the electromagnetic on-off valve 2d of the main flow path 2 is closed, and the electromagnetic on-off valve 42a of one of the span gas flow paths 42 is opened. In this state, the main suction pump 2c introduces span gas from the span gas flow path 42 into the measurement cell 31 of the analyzer 3. This performs span calibration of the analyzer 3. Even if the calibration gas is supplied under pressure from a cylinder, the pressure difference at the connection point 6x when the sample gas ( FIG. 3 ) or the first purge gas ( FIG. 4 ) is flowed through the main flow path 2 can be minimized by opening the gas to the atmosphere using the three-way electromagnetic valve 6d of the overflow flow path 6.

[0045] After the series of operations of the purging process, zero calibration, and span calibration are completed, continuous analysis is performed again. Specifically, when the series of operations are completed, the electromagnetic on-off valve 2d of the main flow path 2 opens, the introduction of sample gas into the analyzer 3 is resumed, and the three-way electromagnetic valve 6d of the overflow flow path 6 closes the bypass path 9, and the exhaust of sample gas through the overflow flow path 6 is resumed (see FIG. 3).

[0046] <At the end of continuous analysis (before or during system shutdown)> When the continuous analysis described above is completed, before or during system shutdown, the three-way valve 2i is switched to supply the second purge gas from the second purge gas flow path 5B, as shown in Fig. 7. Here, the three ports of the three-way valve 2i are in a state in which the port connected to the downstream side of the main flow path 2 is closed, and the port connected to the upstream side of the main flow path 2 and the port connected to the second purge gas flow path 5B are in communication with each other. Note that in the above-mentioned <Normal analysis> and <Calibration (including purging)>, the three ports of the three-way valve 2i are in a state in which the port connected to the second purge gas flow path 5B is closed, and the port connected to the upstream side of the main flow path 2 and the port connected to the downstream side of the main flow path 2 are in communication with each other.

[0047] In this way, the second purge gas is caused to flow back into the main flow path 2 via the three-way valve 2i. As a result, the exhaust gas remaining in the main flow path 2 is purged and discharged to the outside through the sampling unit 7 (second purge process). In this state, the continuous gas analysis system is stopped. Note that in the second purge process in which the second purge gas is supplied from the second purge gas flow path 5B to the upstream side of the main flow path, the first purge gas may be supplied to the downstream side of the main flow path 2 to purge the analyzer 3, etc., as in the above-mentioned <Calibration (including purging)>.

[0048] <Effects of this embodiment> According to the continuous gas analysis system 100 of this embodiment configured as described above, the flow path through which the sample gas of the analyzer 3 flows is purged using the first purge gas containing moisture before the analyzer 3 is calibrated, thereby shortening the time until the reading of the analyzer 3 stabilizes during calibration. Here, because the first purge gas containing moisture is used, the adsorptive components adsorbed to the inner surface of the measurement cell 31 of the analyzer 3 are easily desorbed by water molecules. As a result, the time for calibration performed between continuous analyses can be shortened, and the interruption time of the continuous analysis of the sample gas can be shortened.

[0049] <Other Embodiments> For example, in the gas analysis system 100 of the above embodiment, during normal continuous analysis, the sample gas is sucked by the sub-suction pump 6a and overflows the overflow passage 6, and during calibration, the calibration gas is pressurized and supplied from the calibration gas cylinder in a state where the bypass passage 9 is open to the atmosphere. In other words, in the above embodiment, the pressure at the connection point 6x of the overflow passage 6 is not the same during continuous analysis and during calibration, which affects the internal pressure of the measurement cell 31 and causes a change in the indicated value of the analyzer.

[0050] Therefore, as shown in Figure 8, it is desirable to eliminate the bypass flow path 9 and use a sub-suction pump 6a to suck air through the overflow flow path 6 both during normal continuous analysis and during calibration. A compensation gas inlet path 12, which introduces a compensation gas such as air, is connected to the overflow flow path 6. The compensation gas inlet path 12 is provided with a check valve 12a and an electromagnetic on-off valve 12b. Also, *1 in Figure 8 indicates that the compensation gas inlet path 12 branches off from the first purge gas flow path 5A, and air that has passed through a dust collection filter 51 is introduced into the compensation gas inlet path 12. The compensation gas inlet path 12 may be provided independently of the first purge gas flow path 5A.

[0051] When the calibration gas is pressurized from the calibration gas cylinder and supplied to the measurement cell 31 (during calibration), the electromagnetic on-off valve 12b is opened so that the compensation gas is supplied from the compensation gas flow path 12 to the overflow path 6. This allows the compensation gas to make up for the shortage of the calibration gas flow rate relative to the suction flow rate of the sub-suction pump 6a during calibration. Therefore, the pressure difference at the connection point 6x between during continuous analysis and during calibration can be reduced.

[0052] Furthermore, gas must be supplied at a predetermined flow rate, for example, 1.5 L / min, through the main flow path 2, and if more calibration gas is not supplied from the calibration gas cylinder during calibration, the compensation gas will flow back into the main flow path 2 through the compensation gas flow path 12. For this reason, it is desirable to provide calibration gas flow rate sensors 41d, 42d in each calibration gas flow path 4 (41, 42). With this configuration, the calibration gas supplied to the main flow path 2 can be accurately measured, and the compensation gas can be prevented from flowing back into the main flow path 2 through the compensation gas flow path 12.

[0053] Furthermore, the load on the main suction pump 2c varies between normal continuous measurement and calibration. Therefore, when calibration is performed after continuous measurement and continuous measurement is performed again, the internal pressure of the measurement cell during continuous measurement before calibration and the internal pressure of the measurement cell during continuous measurement after calibration change, resulting in poor reproducibility.

[0054] Therefore, as shown in Figure 8, in order to reduce the load fluctuation of the main suction pump 2c between continuous measurement and calibration, a pressure adjustment flow path 13 is connected in the main flow path 2 between the measurement cell 31 and the main suction pump 2c. Here, the pressure adjustment flow path 13 suppresses load fluctuation of the main suction pump 2c by introducing atmospheric air or the like into the main flow path 2. This pressure adjustment flow path 13 is provided with a dust collection filter 13a and a pressure adjustment valve 13b. This makes it possible to reduce load fluctuation of the main suction pump 2c between continuous measurement and calibration. Furthermore, in order to measure the flow rate of the gas flowing through the measurement cell 31, a flow rate sensor 2i is provided in the main flow path 2 between the connection point of the measurement cell 31 and the pressure adjustment flow path 13.

[0055] In the above embodiment, the zero calibration and span calibration are performed after the first purge process, but the first purge process and zero calibration may be performed simultaneously. In this case, the continuous gas analysis system 100 supplies the first purge gas from the first purge gas flow path 5A to the analyzer 3 during the continuous analysis to purge the analyzer 3 and zero-calibrate the analyzer 3, and then supplies the span gas from the calibration gas flow path 4 to the analyzer 3 to span-calibrate the analyzer 3.

[0056] Furthermore, in the above embodiment, the configuration includes the overflow passage 6, but the configuration may not include the overflow passage 6.

[0057] Furthermore, in the above embodiment, the second purge gas flow passage 5B is provided, but the second purge gas flow passage 5B may not be provided.

[0058] The standard gas flow path 4 in the above embodiment supplies a calibration gas, which is a standard gas for calibrating the analyzer 3, but it may also supply a validation gas, which is a standard gas for validating the analyzer 3. This validation gas is a gas used to confirm the performance of the analyzer 3. By supplying validation gas to the analyzer 3, the performance of the analyzer 3 can be confirmed.

[0059] Furthermore, although the analyzer 3 in the above embodiment uses an IRLAM detector, it may also be a detector using an infrared absorption method, such as a detector using non-dispersive infrared absorption (NDIR) or a detector using Fourier transform infrared spectroscopy (FTIR).

[0060] In addition, as shown in FIG. 9 , the continuous gas analysis system of the present invention includes a sampling unit 7 that samples gas containing adsorbent components flowing through a duct, a main flow path 2 through which the sample gas sampled by the sampling unit 7 flows, a chromatograph or mass spectrometer 11 that analyzes the adsorbent components in the sample gas flowing through the main flow path 2, and an overflow flow path 6 that discharges a portion of the sample gas flowing through the main flow path 2 upstream of the chromatograph or mass spectrometer 11. Examples of the chromatograph include an ion chromatograph and a gas chromatograph. Note that components in FIG. 8 that are designated by the same reference numerals as in the above embodiment are the same as in the above embodiment. With this configuration, the overflow flow path 6 allows the sample gas introduced into the main flow path 2 to have a large flow rate. As a result, it is possible to make it difficult for adsorbent components to be adsorbed on the inner surface of the piping that constitutes the main flow path 2, thereby improving the accuracy of analyzing trace amounts of adsorbent components using the chromatograph or mass spectrometer 11.

[0061] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention.

[0062] According to the present invention, it is possible to reduce the time required for calibration or validation of an analyzer that analyzes a sample gas containing an adsorbent component.

[0063] 100: Infrared gas analyzer 2: Main flow path 3: Analyzer 4: Calibration gas flow path (standard gas flow path) 41: Zero gas flow path 42: Span gas flow path 5A: Purge gas flow path (first purge gas flow path) 5B: Second purge gas flow path 6: Overflow flow path 2b: Throttle section 2c: Main suction pump 6a: Sub-suction pump

Claims

1. a main flow path through which a sample gas containing an adsorbent flows; an analyzer for analyzing an adsorbable component in the sample gas flowing through the main flow path; a calibration gas flow path for supplying a calibration gas to the analyzer; a purge gas flow path for supplying a purge gas containing moisture to a flow path through which the sample gas of the analyzer passes; A continuous gas analysis system, comprising: introducing a sample gas into the main flow path and continuously analyzing the sample gas using the analyzer; supplying the purge gas from the purge gas flow path to the analyzer during the continuous analysis to purge a flow path of the analyzer through which the sample gas passes; and subsequently supplying a calibration gas from the calibration gas flow path to the analyzer to calibrate the analyzer.

2. 2. The continuous gas analysis system of claim 1, wherein the purge gas flow path supplies atmospheric air to a flow path of the sample gas in the analyzer.

3. The analyzer detects the adsorbable components HF, HCl, or NH ３ 3. The continuous gas analysis system according to claim 1, which is adapted to analyze:

4. The calibration gas flow path includes: a zero gas flow path that supplies a zero gas to the analyzer; a span gas flow path for supplying a span gas to the analyzer; 3. The continuous exhaust gas analysis system according to claim 1, wherein, during the continuous analysis, the purge gas is supplied from the purge gas flow path to the analyzer to purge a flow path of the analyzer through which the sample gas passes, followed by supplying zero gas from the zero gas flow path to the analyzer to zero calibrate the analyzer, and supplying span gas from the span gas flow path to the analyzer to span calibrate the analyzer.

5. the calibration gas flow path supplies a span gas to the analyzer; 3. The continuous exhaust gas analysis system according to claim 1, wherein, during the continuous analysis, the purge gas is supplied from the purge gas flow path to the analyzer to purge a flow path of the analyzer through which the sample gas passes and the analyzer is zero-calibrated, and subsequently, a span gas is supplied from the calibration gas flow path to the analyzer to span-calibrate the analyzer.

6. a second purge flow path connected to the upstream side of the analyzer in the main flow path and configured to supply a second purge gas from the connection point toward the upstream side of the main flow path; 3. The continuous exhaust gas analysis system according to claim 1, wherein the second purge gas is supplied from the second purge passage after the continuous analysis is completed, to purge an area upstream of a connection point of the second purge passage.

7. 3. The continuous gas analysis system according to claim 1, further comprising an overflow passage for discharging a part of the sample gas flowing through the main passage upstream of the analyzer.

8. a throttle portion is provided in the main flow path between the connection point of the overflow flow path and the analyzer, and a main suction pump is provided in the main flow path downstream of the analyzer, The continuous gas analysis system according to claim 7 , further comprising a sub-suction pump provided in the overflow passage.

9. a sampling unit that samples the gas containing the adsorbent flowing through the duct; a main flow path through which the sample gas sampled by the sampling unit flows; a chromatograph or mass spectrometer for analyzing an adsorbable component in the sample gas flowing through the main flow path; and an overflow passage for discharging a portion of the sample gas flowing through the main passage upstream of the analyzer.

10. A method for continuous gas analysis using a measurement system including a main flow path through which a sample gas containing an adsorbent flows, an analyzer for analyzing the adsorbent in the sample gas flowing through the main flow path, a calibration gas flow path for supplying a calibration gas to the analyzer, and a purge gas flow path for supplying a purge gas containing moisture to a flow path of the analyzer through which the sample gas passes, comprising: A method for continuous gas analysis, comprising: introducing the sample gas into the main flow path, continuously analyzing the sample gas using the analyzer, supplying the purge gas from the purge gas flow path to the analyzer during the continuous analysis to purge a flow path of the analyzer through which the sample gas passes, and subsequently supplying a calibration gas from the calibration gas flow path to the analyzer to calibrate the analyzer.